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Topic:Horse Breeds
Horse breeds represent the diverse genetic and phenotypic variations found within the species Equus ferus caballus. These breeds are categorized based on characteristics such as size, conformation, coat color, and temperament, which have been selectively bred over centuries to fulfill specific roles and functions. Common classifications of horse breeds include light horses, draft horses, and ponies, each serving different purposes ranging from riding and racing to work and companionship. This page aggregates peer-reviewed research studies and scholarly articles that explore the genetics, history, and functional attributes of various horse breeds, as well as their impact on equine management and breeding practices.
SNARE proteins and caveolin-1 in stallion spermatozoa: possible implications for fertility. Proteins implicated in the "SNARE hypothesis" for membrane fusion have been characterized in the acrosome of several mammalian species, and a functional role for these proteins during the acrosome reaction has been proposed. We have investigated the presence of SNAREs in equine sperm, using semen samples obtained from stallions with varying fertility. Immunocytochemical analysis revealed that members of different SNARE families can be detected on the acrosome of equine sperm, notably in the acrosomal cap and equatorial segment. These proteins include the t-SNARE syntaxin, the v-SNARE synaptobr...
The effect of varying dietary starch and fat content on serum creatine kinase activity and substrate availability in equine polysaccharide storage myopathy. The effect of dietary starch and fat content on serum creatine kinase (CK) activity and substrate availability was evaluated in 4 mares of Quarter Horse-related breeds with polysaccharide storage myopathy (PSSM). Four isocaloric diets ranging in digestible energy (DE) from 21.2% (diet A), 14.8% (B), 8.4% (C), to 3.9% (D) for starch, and 7.2% DE (diet A), 9.9% (B), to 12.7% DE (diet C and D) for fat were fed for 6-week periods (4 weeks with exercise) using a 4 X 4 Latin square design. Postprandial glucose and insulin responses were measured, and 4 hours postexercise, serum CK activity, glucose,...
Helminths in horses: use of selective treatment for the control of strongyles. The current level of anthelmintic resistance in the horse-breeding industry is extremely high and therefore more emphasis is being placed on studies that focus on the judicious use of anthelmintic products. The aims of the study were to: 1) establish if there is variation in the egg excretion pattern of strongyles between the different age classes of Thoroughbred horses in the Western Cape Province (WCP), 2) test if a selective treatment approach successfully reduces the number of anthelmintic treatments and maintains acceptably low helminth burdens in adult Thoroughbred horses, and 3) evaluat...
Expression and subcellular localization of the mu-opioid receptor in equine spermatozoa: evidence for its functional role. The development of fertilizing ability in sperm cells is associated with changes in the plasma membrane. However, to date the exact nature of sequentially activated primary receptors and channels and the signal transduction pathways derived from these remains elusive. We analyzed the expression and localization of the mu-opioid receptor in equine spermatozoa. A transcript corresponding to the third extracellular loop that selectively binds mu agonists was amplified, sequenced and compared with the known sequences in humans, rats and cattle. The amplification product showed a high degree of nuc...
Sources and magnitude of variation of echocardiographic measurements in normal standardbred horses. The purpose of this study was to assess the intraobserver variation of various echocardiographic measures in standardbred trotters. Serial echocardiographic examinations were carried out on eight standardbred mares by one ultrasonographer for 5 separate days. During each examination, five nonconsecutive cardiac cycles (frames) were recorded and an average obtained for each individual measure. Various echocardiographic measures were obtained by use of two-dimensional (2-D), M-mode, color flow Doppler and pulsed wave Doppler echocardiography. The total variation in the echocardiographic measurem...
Effect of insemination dose and site on uterine inflammatory response of mares. It is unclear whether AI of mares deep into the uterine horn causes more or less inflammation of the endometrium than conventional AI. Thus, we compared uterine inflammatory reactions of mares inseminated with two different doses of frozen-thawed semen into the tip of the uterine horn (UH) ipsilateral to the preovulatory follicle with those of mares inseminated into the uterine body (UB). Thirty-two mares were assigned to one of four groups (eight mares/group): UB20=AI into UB, 20 x 10(6)sperm/0.5 mL; UB200=AI into UB, 200 x 10(6)sperm/0.5 mL; UH20=AI into UH, 20 x 10(6)sperm/0.5 mL; UH200=AI ...
Effects of glutamine on post-thaw motility of stallion spermatozoa: an approach of the mechanism of action at spermatozoa level. The cryoprotective effect of l-glutamine and an approach of its mechanism of action, in preserving motility of stallion spermatozoa during the freezing-thawing process, were studied. In Experiment 1, thirty-six ejaculates were collected from six stallions (two good, two middle, and two of poor sperm freezability) and were diluted with 10 different freezing media derived from INRA 82 medium supplemented with 20 mM HEPES and 2% (v/v) centrifuged egg yolk (BM). After thawing, sperm motility was evaluated by a computer-assisted semen motility analyser. The effects of glutamine and glycerol at diff...
Prevalence and demographic characteristics of exertional rhabdomyolysis in horses in Australia. The proportion of the horses, of both sexes and of different ages, breeds and levels of activity, owned by a stratified random sample of Australian owners, which had suffered one or more episodes of exertional rhabdomyolysis during the previous 12 months was determined. The proportion in the general population was 1.9 per cent, and horses which exercised were significantly more likely to have experienced the condition than horses which did not. There were significant differences between the sexes and between certain breeds and activity groups in the proportions of horses affected.
Sperm morphology in Estonian and Tori breed stallions. The standard procedure for assessing the breeding potential of a stallion includes the parameter total number of spermatozoa classified as morphologically normal. This study investigated sperm morphology of fresh semen in randomly chosen Estonian (E, n = 8) and Tori (T, n = 7) breed stallions with proven fertility. Two ejaculates were examined from each stallion. An aliquot from each ejaculate was fixed in 1 mL formol-saline immediately after collection and examined with phase-contrast microscope at a magnification 1000x for all types of morphological abnormalities. Furthermore smears were pre...
A Bayesian approach to prediction of stallion daily sperm output. In equine breeding, the number of spermatozoa ejaculated is considered an important factor in fertility. Methods for predicting the number of spermatozoa have been derived from semen collection procedures. A once-daily collection period for 10 days is a standard recommendation to predict long-term daily sperm output (DSO). The first objective of this study was to determine the precision or repeatability of these DSO predictions. Semen was collected and evaluated daily during four periods for 10 days, for 15 different stallions. The analytical methods utilized hierarchal Bayesian modeling as im...
Influence of weight bearing and hoof position on Doppler evaluation of lateral palmar digital arteries in healthy horses. To describe the pulsed-wave Doppler tracing of the equine lateral palmar digital artery and its modification in relation to standardized changes in posture. Methods: 17 healthy Saddlebred horses. Methods: Pulsed-wave Doppler examinations of left and right lateral palmar digital arteries of the horses were performed. The baseline examination was performed on each forelimb while horses were standing squarely with the body weight equally distributed among the 4 limbs (BED position). For each forelimb, the examination was repeated during 3 standardized modifications of the horse's posture (non-wei...
[The domestic animal in heraldry; Part 3, the horse]. The author presents in her paper the historical background of the heraldic. In the coming four papers she will discuss the use and position of different domestic animals in heraldic.
Experience from Lipizzan horse and salmonid species endemic to the Adriatic river system. Examples for the application of molecular markers for preservation of biodiversity and management of animal genetic resources. Management of breeding- and free-living populations, traditionally based on phenotypic traits, relays more and more on availability of reliable information about the basic population genetic parameters as heterozygosity, mean number of alleles per locus, percentage of polymorphic loci, population structuring, genetic distances and others. Therefore, the application of molecular markers, revealing a great deal of phenotypically hidden information, becomes inevitable for population analysis. Conservation geneticists use this information for implementation of appropriate management policies. Appl...
Skeletal atavism in a miniature horse. An 8-month-old miniature horse filly was presented for evaluation of severe rotational and angular limb deformities of the thoracic and pelvic limbs. On radiographic examination, complete ulnas and fibulas were identified. These findings are consistent with a condition previously described as a form of atavism. The term atavism is used to describe the reappearance of a trait or character that was seen in all earlier evolutionary specimens of a particular species, but has not been seen in recent ancestors. The atavistic traits of complete ulnas and fibulas have previously been described in Wels...
Association of a mutation in the ryanodine receptor 1 gene with equine malignant hyperthermia. Equine malignant hyperthermia MH has been suspected but never genetically confirmed. In this study, we investigated whether mutations in a candidate gene, RyR1, were associated with MH in two clinically affected horses. RyR1 gene sequences revealed polymorphisms in exons 15, 17, and 46 in WTRyR1 and MHRyR1 horses with one derived amino acid change in MHRyR1 exon 46, R2454G. The MHRyR1 horses were genetically heterozygous for this mutation, but presented an MH phenotype with halothane challenge. Skeletal sarcoplasmic reticulum from a R2454G heterozygote collected during a fulminant MH episode s...
Equine congenital papilloma: pathological findings and results of papillomavirus immunohistochemistry in five cases. Abstract Congenital cutaneous papillomas were identified in five foals. Age at diagnosis ranged from 305 days' gestation to 2 days of age. Breeds were thoroughbred (2), standard-bred (1), warmblood (1) and paint (1). Two were female, one was male and the gender of two cases was not specified. Masses were pedunculated with a roughened, wart-like (verrucous) or a smoother, cauliflower-like surface. Masses occurred as single lesions on the forelimb, lip and face, or as multiple lesions on the trunk. Histological features included relatively uniform epidermal papillary hyperplasia with variable me...
Step-wise dilution for removal of glycerol from fresh and cryopreserved equine spermatozoa. Osmotic stress is an important component of the damage to spermatozoa during cryopreservation. Osmotic injury, due to hyperosmolar freezing extenders, changes in relative solute concentration in the extra cellular medium during freezing and differences in the relative permeabilities of penetrating cryoprotectants, such as glycerol, and water occur when cryopreserved spermatozoa are diluted into isosmotic media or when spermatozoa are placed in the female reproductive tract. The purpose of the study reported here was to evaluate the effect of step-wise dilution for the removal of the permeating...
Effect of matrix depleting agents on the expression of chondrocyte metabolism by equine chondrocytes. This study was carried out to investigate the effect of two enzymes (collagenase and chondroitinase) and two cytokines/metabolites (interleukin-1beta and retinoic acid) of known catabolic activity on the expression of cartilage metabolism/phenotype in equine articular cartilage. Articular cartilage explants from 11 horses (5-13 years old) were treated for 48 h and assayed for total sulphated glycosaminoglycan (GAG), the incorporation of 35S-sulphate, collagen degradation and mRNA expression of the proteoglycans collagen II, collagen IIA, collagen III, collagen IX, collagen X, collagen XI and g...
Low dose insemination in the mare: an update. The generally recommended minimum number of spermatozoa required for conventional artificial insemination in the mare is in excess of 200 x 10(6) progressively motile spermatozoa. Recent developments in different insemination techniques such as deep uterine, hysteroscopic and oviductal insemination, which have been designed to use significantly fewer spermatozoa, are reviewed in this paper. A number of studies have demonstrated that ultrasound guided deep uterine insemination of 5 x 10(6) fresh spermatozoa can produce satisfactory pregnancy rates. The use of hysteroscopic insemination enables ...
Microsatellite diversity, population subdivision and gene flow in the Lipizzan horse. Blood samples of 561 Lipizzan horses from subpopulations (studs) of seven European countries representing a large fraction of the breed's population were used to examine the genetic diversity, population subdivision and gene flow in the breed. DNA analysis based on 18 microsatellite loci revealed that genetic diversity (observed heterozygosity = 0.663, gene diversity = 0.675 and the mean number of alleles = 7.056) in the Lipizzan horse is similar to other horse breeds as well as to other domestic animal species. The genetic differentiation between Lipizzan horses from different studs, although...
Genetic diversity in German draught horse breeds compared with a group of primitive, riding and wild horses by means of microsatellite DNA markers. We compared the genetic diversity and distance among six German draught horse breeds to wild (Przewalski's Horse), primitive (Icelandic Horse, Sorraia Horse, Exmoor Pony) or riding horse breeds (Hanoverian Warmblood, Arabian) by means of genotypic information from 30 microsatellite loci. The draught horse breeds included the South German Coldblood, Rhenish German Draught Horse, Mecklenburg Coldblood, Saxon Thuringa Coldblood, Black Forest Horse and Schleswig Draught Horse. Despite large differences in population sizes, the average observed heterozygosity (H(o)) differed little among the heavy ...
What is the likelihood that Thoroughbred foals treated for septic arthritis will race? Septic arthritis is a serious problem in the neonate, with a poor prognosis being reported for recovery. The impact of neonatal septic arthritis on the likelihood that Thoroughbred (TB) foals will start on a racecourse is not known. Objective: The development of septic arthritis in a TB foal significantly reduces the likelihood that it will race when compared to foals from the same dam. Methods: Medical records of 69 foals treated for septic arthritis were reviewed. The dam's foaling records were reviewed and lifetime racing records were then retrieved for both the affected foals and at least ...
Effects of different artificial insemination techniques and sperm doses on fertility of normal mares and mares with abnormal reproductive history. The effects of different artificial insemination (AI) techniques and sperm doses on pregnancy rates of normal Hanoverian breed mares and mares with a history of barrenness or pregnancy failure using fresh or frozen-thawed sperm were investigated. The material included 187 normal mares (148 foaling and 39 young maiden mares) and 85 problem mares with abnormal reproductive history. Mares were randomly allotted into groups with respect to AI technique (routine AI into the uterine body, transrectally controlled deep intracornual AI ipsilateral to the preovulatory follicle, or hysteroscopic AI onto...
[The influence of centrifugation on quality and freezability of stallion semen]. The aim of the present study was to investigate the influence of various centrifugation methods on sperm loss and quality of frozen-thawed semen. From at a total of 8 Warmblood stallions of the National Stud Farm in Avenches, 3 ejaculates each were collected and seminal plasma was removed using 3 different centrifugation regimes. In method I (reference method) centrifugation occurred by a speed of 600 x g during 10 minutes. In method II 1000 x g was used during 2 minutes while in method III centrifugation was performed by 2000 x g during 2 minutes. After centrifugation 90%, of the supernatant ...
